HIGH ACCURACY TEMPERATURE CONTROL
A flaker system was installed to produce new products as part of a multi-million dollar expansion in a generic pharmaceutical manufacturing facility. Trials were performed on a flake making system that would combine active ingredients with melted carriers. The product would then be solidified on the cooled drum of the flaker and scraped into containers for further processing.
In a flaking system, ingredients are combined and melted in a kettle with a heating jacket. The molten product is then released from the bottom of the kettle into the flaking machine, which has a small hot roll and a large cold roll in close proximity to each other. The product flows into the “nip” between the rolls.
The hot roll keeps the product molten. The cold roll picks it up and cools it as it rotates. The product is solidified by the time it reaches the scraping blade, where it is scraped off and falls into a collection container.
High accuracy temperature control is needed to keep the product molten but not heat it any more than necessary. An additional challenge was that different products with different melting points would be processed so the temperature set points were variable. JNE designed a system to control the heating and cooling of the product to very strict tolerances. The flake making system was designed to:
- Be capable of operating three eight-hour shifts per day, five days per week.
- Have batch heating times in the order of five hours utilizing the available utilities.
- Permit a wide range of operating variability by utilizing variable speed components with turndown capability of at least 50%.
- Utilize heating and cooling equipment and necessary controls to control making temperatures to within 4°C of maximum recipe set-points.
- Include a batch making control system suitable for manually stepping through a recipe while automatically controlling the various processes within each step and permit fine tuning of parameters to permit very fine temperature control around critical temperature set-points.
- Minimize changeover times between different recipes.
- Utilize FDA approved components when available.
To provide this control, JNE engineered a hot/cold thermal oil system complete with a new chiller and a steam/oil heat exchanger that met the demanding control requirements.